Mechanical process for making ready impressions



Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE MECHANICAL PROCESS FOR MAKING No Drawing. Application September 27, 1934, Serial No. 745,801

1 Claim.

Mechanical process for making ready for printing, that is compensating the differences in pressure which arise when the platen or cy1- inder of a printing press is applied to a form of type, etc. which has not been made ready, for the purpose of giving clear and uniform impressions.

A process is known in which an impression of the form to be made ready was taken on a specially prepared surface. This impression was then used as the negative or copy-sheet, and a relief exhibiting all the irregularities of the form was made on a special sensitized foil or sheet.

The present invention is a modification of the above process, and consists in producing an impression of the make ready directly in relief or in other words, omitting the copy-sheet, and in such a way as to give clear-cut as distinct from blurred or spreading and smudgy impressions. The method described in the present invention considerably simplifies the process of making ready.

The present process involves the use of a flat or round, stiff or pliableirnpression surface suitably prepared for taking clear-cut impressions, in place of the thin impress foil, carbon paper.

One method of carrying out the process is as follows: A wax composition, say, one consisting of 20 parts beeswax, 2 parts Vaseline or petroleum jelly, 15 parts extra-finely powdered graphite, colloidal graphite, and 5 parts soft soap, is applied to the platen or cylinder of the printing press.

Alternatively, a special foil or sheet, inserted between the form and the impression surface, may be used. The counter-relief surface, with (Cl. ll-25.5)

a backing sheet behind, is then subjected one or more times, as required, to the initial pressure until the heavy details of the type, etc. show on it.

Depending on the composition of the material, the make-ready sheet is then stiffened or hardened by coating or spraying it with a varnish of suitable type, or liquid solutions, or dusting it with asphalt, etc. Instead of the hardening medium being applied directly to the make- 1 ready sheet, the composition can be hardened by placing in contact with it a sheet of paper impregnated with the hardening liquid. After the hardening medium has been dried and set, which process can be accelerated by exposing it to a stream of warm air, it is impossible for the counter-relief, or matrix, to spread or wear due to the pressure between the platen or cylinder and the form.

In cases where absolute accuracy is not essential, as for instance, when preparing makeready plates or for compensating the solids in half-tone blocks, etc., an interlay of cardboard or of pasteboard of suitable thickness can be inserted while the impression of the form is being taken, so as to correct for the solids of small area in the blocks, etc.

What I claim is:

A process of producing make-readies for printing comprising first preparing a layer consisting of about 20 parts beeswax, 2 parts petroleum jelly, 15 parts powdered graphite and 5 parts soft soap, then applying said layer to the platen of a printing press, taking impressions of the form on said layer and finally hardening the layer.

FRIEDRICH KARL FLE'ISCHI-IACK. 

